Flow and static cytometric techniques have become indispensable to biomedical researchers and clinicians. Laser scanning cytometry and volumetric capillary cytometry can be used to perform measurements similar to those performed in flow cytometers, while allowing utilization of smaller samples and repeated analysis of single cell over time. While many of the fluorescent reagents used in cytometry can be excited with the 488 nm argon ion lasers commonly used, many extremely useful probes require ultraviolet (UV) or violet excitation. Arc lamp sources can provide UV and violet excitation for cytometry, however they are noisy and difficult to use in combination with visible lasers in multibeam flow cytometers. We propose to build an alexandrite-based, diode-pumped, solid-state, CW, UV laser. The compact laser will be configured to operate at a fixed wavelength near 375 nm, but can be modified to continuously tune over the 360-405 nm range. For Phase I, it will produce at least 1 mW of UV with a TEM 00 spatial mode and stability better than scanning laser cytometers, and confocal microscopes.